Separable attachment-plug.



C. G. COPE.

SEPARABLE ATTACHMENT PLUG. APPLICATION FILED APR. 5, ma.

Patented Aug. 7,1917.

CHARLES G. COPE, OF CHICAGO, ILLINOIS, ASSIGNOR T0 BENJAMIN ELECTRICMFG. COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

SEPABABLE ATTACHMENT-PLUG.

To all whom it may concern:

Be it known that 1, CHARLES G. COPE, a subject of the King of GreatBritain, residing at Chicago, in the county of Cook and State ofIllinois, have invented new and useful Improvements in SeparableAttachment-Plugs, of which the following is a full, clear, concise, andexact description, reference being had to the accompanying drawing,forming a part of this specification.

My invention pertains to separable attachment plugs, that is to say, toplugs of the kind which comprise an insertible member adapted to bescrewed into a lamp socket or the like, and a binding-terminal carryingmember which is separably connected with the insertible member. It isthe principal object of my invention to simplify the construction ofplugs of this character, as well as to provide a plug which will beconvenient and safe in use.

A separable attachment plug constructed in accordance with my inventionis described, by way of example, in the following specification andshown in the accompanying drawing, in which:

-Figure'1 is a longitudinal section through the plug, showing theinsertible mem er and the binding-terminal carrying member in theirconnected condition, the section being taken on the line 11 of Fig. 3;

Fig. 2 shows a portion of the insertible member in side elevation andshows the binding-terminal carrying member in longitudinal section, suchsection being taken on the line 22 of Fig. 3. r

Fig. 3 is a plan of the binding terminal carrying member, and

Fig. 4 is a section on the line 44 of Fig. 1 looking in the'direction ofthe arrows.

Referring now to the drawing, the insertible member comprises a threadedcontact 10 having molded on the lower end thereof an insulating thumbring 11. The threaded contact is formed with an inwardl extending flange12 just above the thumb ring 11 and with a second inwardly extendingflange 13 at its top end. An insulating block 14 is contained betweenthe flanges 12 and 13, and is of such diameter as to fit snugly into thethreaded contact 10 while still permitting of free relative rotationbetween itself and the threaded contact. The insulating block 14 isformed with an extension 15 of reduced diameter which termi-Specification of Letters Patent.

' 26, a binding plate 27 carrying Patented Aug. 7, 1917.

Application filed April 5, 1913. Serial No. 759,138.

nates' flush with the lower face of the insulating ring 11, therebyproducing an annular chamber 16 within the inner edge of the ring 11.The threaded contact 10 is formed with a neck which extends downwardlyat the inside of the ring 11, the lower portion, 17, of this neck beingimbedded in the material of the ring 11 so as to be hidden and protectedthereby. The upper portion, 18, of this neck is exposed and is formedinto a hollow bead for receiving the spring contacts of thebinding-terminal carrying member, in the manner described below.

The insulating block 14 is formed, at its lower end, with a centralrectangular chamber 19 which contains a forked spring contact 20. Theforked contact 20 has the ends 21 thereof flared outwardly to receivethe center contact of the binding-terminal carrying member. The contact20 is clamped in position by means of a nut 22 which receives a screw 23which passes longitudinally through the insulating block 14. A dishedwasher 24 is clamped between the head of the screw 23 and the top end ofthe block 14, this washer forming the center contact of the insertiblemember.

The binding-terminal carrying member of the plug comprises an insulatingbase 25 having secured thereto, by means of a screw a binding screw 28.The binding plate is bent to form an upwardly extending flat shank 29situated centrally of the base 25, the upper end of which shank is bentto form a wedge shaped head 30. The shank 29 and the head 30 are of suchlength that the head will enter between the outwardly flared ends 21 ofthe forked contact 20, forcing them apart, when the binding-terminalcarrying member is connected with the insertible member, wherebyconnection is made between the center contact 24 of the insertiblemember and the binding screw 28 of the binding-terminal tending springcontact tongues 35, each of which is bent to form a rounded head 36. Thelength and position of the tongues 35 is such that their heads will snapinto the hollow bead 18 of the insertible member when thebinding-terminal carrying member is thrust toward the insertible member.The tongues 35 perform the mechanical function of releasably connectingthe binding-terminal carrying member with the insertible member, and atthe same time make electrical connection with the binding screw 34 andthe threaded contact 10.

The insulating base 25 has a conductor-re ceiving passage 37 formedtherethrough, which passage connects, by a channel 38, with the bindingscrew 28. The insulating base is also formed with a second passage 39being opposed diametrlcally 39 for permitting a conductor to be broughtto the binding screw 34, the passages 37 and to each other. The cap 31is provided w1th a down wardly extending threaded neck 40, into which isscrewed an insulating bushing 41 having a central aperture 42 forpermitting the passage of the conductors therethrough. The bushing 41 isformed with an upwardly extending flange '43 which'surrounds the cap 31and base 25 when the bushing is screwed into the neck 40. When thebushing is screwed into the neck 40 its upper edge clamps the conductorsleading from the binding screws 28 and 34 against the lower part of thebase 25, whereby the binding screwsare relieved from all strain.

When the insertible member is connected with the binding-terminalcarrying member, the threaded contact 10 may be rotated with respect tothe remainder of the plug, whereby insertion of the plug into a socketis facilitated. and twisting of the conductors avoided. By reason of theshape of the contact head 30 and forked contact 20, the insulating block14 remains stationary with respect to the binding-terminal carryingmember, the blockthus becoming clamped into the. socket when thethreaded contact 10 is screwed firmly therein. The binding-terminalcarrying member can be separated from the insertible member, orconnected thereto, with great ease, itbeing only necessary to overcomethe resiliency of the sprin contacts 35. The shape and arrangement 0 ithe parts is such that the binding-terminal carrying member will beseparated from the insertible member whenever a pull is exercised on theconductors, regardless of the direction in which said pull may beapplied. When the binding-terminal carrying member is removed from theinsertible member, the extension 15 of the base 14 separates the forkedcontact 20 from the neck 17 of the threaded contact 10, thus preventingthese contacts from being bridged by reason of a conducting member beingaccidentally put into the insertible member. Similar accidents due to aperson touching both of the contacts of the insertible membersimultaneously are prevented. By reason of the fact that the contact 20terminates considerably short of the mouth of the chamber,

it would be very diflicult to touch this contremely simple constructionand may beplaced on the market at a low cost.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is 1. A separable attachment plug comprising aninsertible member including an insulating block, and a threaded contactmounted to rotate with respect to said block and having an exposedannular portion; and an insulating binding-terminal carrying memberseparably connected with said insertible member and a contact slidablyengaging the annular portion of said rotatable threadedcontact when themembers are connected together, said slidable contact being supported bysaid binding terminal carrying member.

2. A separable attachment plug comprising an insertible member includingan insulating block, and a threaded contact mounted to rotate withrespect to said block and having an exposed annular portion; and abinding-terminal carrying member separably connected with saidinsertible member and including a contact slidably engaging the annularportion of said rotatable threaded contact when the members areconnected v together, and means for preventing relative rotation betweensaid binding-terminal car-' rying member andsaid insulating block.

3. A separable attachment plug comprising an insertible member includingan insulating block having a reduced extension at its lower end saidextension having an aperture therein, a threaded contact mounted torotate with respect to said block and having an exposed portion oppositesaid exten-' sion, and a contact mounted in said aperture; and abinding-terminal carrying mem ber separably connected with saidinsertible member and including a contact entering between saidextension and said threaded contact and slidably engaging the exposedportion of the latter when the members are connected together, and asecond contact entering said aperture and'engaging'the'contact therein.

4. A separable attachment plug comprising an insertible member includingan in sulating block having a reduced extension at its lower end saidextension having .an aperture therein, a threaded contact mounted torotate with respect to said block and having an exposed portion oppositesaid extension, and a contact mounted in said aperture; and abinding-terminal carrying member separably connected with saidinsertible member and including a contact entering between saidextension and said threaded contact and slidably engaging the exposedportion of the latter when the members are connected together, and asecond contact entering said aperture and engaging the contact therein,said second contact engaging the walls of said aperture, said contactand walls being shaped to prevent relative rotation between saidbinding-terminal carrying member and said insulating block.

5. An attachment plug comprising an insulating block, center and shellcontacts carried by said block, said block having an axial recesstherein, a contact in said recess connected with said center contact,said block having a recess therein off-set from the axis thereof and awall separating said axial and ofi-set recesses and a contact from saidoff-set recess connected with said shell contact, neither of thecontacts insaid recesses extending outwardly beyond the wall separatingthem, an insulating handle portion, and contacts supported therebyextending into said recesses, respectively, forquick detachableengagement with the contacts therein. I

In witness whereof, I have hereunto subscribed my name in the presenceof two wit nesses.

i CHARLES G. COPE.

Witnesses I J OHN TAYLOR, ANNE SoLoMoN.

